JP4815159B2 - Method and apparatus for plating semiconductor wafers - Google Patents

Description

  In the manufacture of semiconductor devices such as integrated circuits and memory cells, a series of manufacturing steps are performed to form a characteristic structure on a semiconductor wafer. A semiconductor wafer includes an integrated circuit device having a multilayer structure formed on a silicon substrate. A transistor device having a diffusion region is formed on each substrate. In subsequent steps, the interconnect metal lines are patterned and electrically connected to the transistor device to form the desired integrated circuit device. Further, the patterned conductive layer is insulated from other conductive layers by a dielectric material.

  A series of manufacturing steps to form a structure on a semiconductor wafer can include an electroplating process that adds material to the surface of the semiconductor wafer. Conventionally, electroplating has been performed using a complete wafer electroplating process performed with the entire wafer immersed in an electrolyte. During the conventional electroplating process, the wafer was maintained at a negative potential relative to the positively charged anode plate, and the anode plate was sized substantially equal to the wafer. The anode plate is also immersed in the electrolyte and maintained in a parallel position close to the wafer.

  During the plating process, the wafer acts as a cathode. Therefore, the wafer needs to be electrically connected to a large number of electrodes. In order to achieve a uniform current distribution across the wafer, a large number of electrodes must be distributed uniformly around the wafer and have approximately the same contact resistance. In a full wafer electroplating processor, if the current distribution across the wafer is non-uniform, there may be a non-uniform plating thickness across the wafer.

  While conventional full wafer electroplating processors can deposit material on the surface of the wafer, the need to continue research and development of improvements in electroplating technology applicable to material deposition in the semiconductor wafer manufacturing process, Always exists.

In one embodiment, an apparatus for electroplating a semiconductor wafer is disclosed. The apparatus includes a wafer support configured to hold a wafer. The apparatus further includes a first electrode disposed at a first position proximate to the outer periphery of the wafer support. The first electrode can be moved for electrical connection and disconnection from the wafer held by the wafer support. The apparatus further includes a second electrode disposed at a second position proximate to the outer periphery of the wafer support. The second position is substantially opposite the first position with respect to the wafer support. The second electrode can be moved for electrical connection and disconnection from the wafer held by the wafer support. The apparatus further includes an anode configured to be disposed above the upper surface of the wafer held by the wafer support. The anode includes a rectangular surface region configured to be substantially parallel to the upper surface of the wafer and proximate to the upper surface of the wafer. The rectangular surface region has a first dimension that is greater than or equal to the diameter of the wafer. The rectangular surface area is further defined by a second dimension that is less than the diameter of the wafer. In addition, the anode and the wafer support are in a direction connecting the first electrode and the second electrode so that the anode can traverse the entire upper surface of the wafer when the wafer is held on the wafer support. It is configured to move relatively.

In another embodiment, an apparatus for electroplating a semiconductor wafer is disclosed. The apparatus includes a wafer support configured to hold a wafer. The apparatus further includes a first electrode disposed at a first position proximate the outer periphery of the wafer support, the first position being along the first semi-perimeter of the wafer support. The first electrode is further configured to be movable so as to be in electrical contact with the wafer held by the wafer support. The apparatus further includes a second electrode disposed at a second position proximate to the outer periphery of the wafer support, the second position being along the second semi-perimeter of the wafer support. The second semi-perimeter of the wafer support part excludes the first semi-perimeter of the wafer support part. The second electrode is further configured to be movable so as to be in electrical contact with the wafer held by the wafer support. In addition, the apparatus includes an anode configured to be disposed above the upper surface of the wafer held by the wafer support. The anode includes a rectangular surface region configured to be substantially parallel to the upper surface of the wafer and proximate to the upper surface of the wafer. The rectangular surface region has a first dimension that is greater than or equal to the diameter of the wafer and a second dimension that is less than the diameter of the wafer. In addition, the anode and the wafer support are relative to each other in the direction connecting the first electrode and the second electrode so that the anode can traverse the entire top surface of the wafer when the wafer is held on the wafer support. Configured to move.

  In another embodiment, a semiconductor wafer electroplating system is disclosed. The system includes a wafer support structure defined to hold a wafer. The system further includes an anode configured to traverse the wafer support structure from the first location to the second location. Each of the first position and the second position is outside the outer periphery of the wafer support structure and is close to the outer periphery of the wafer support structure. The anode is further configured to contact the meniscus of the electroplating solution between the horizontal surface of the anode and the top surface of the wafer when the wafer is held on the wafer support structure. The horizontal surface of the anode has a rectangular area that extends along a first chord that traverses the wafer held by the wafer support structure. Further, the first string is substantially perpendicular to the second string extending from the first position to the second position. The system is further configured to be movable to be in electrical contact with the wafer at a first contact position substantially proximate to the first position when the wafer is held on the wafer support structure. Electrode. In addition, the system is configured to be movable in electrical contact with the wafer at a second contact position substantially proximate to the second position when the wafer is held on the wafer support structure. Includes two electrodes.

  In another embodiment, a method for electroplating a semiconductor wafer is disclosed. The method includes contacting the first electrode to the wafer at a first position. The method further includes traversing the anode at the upper surface of the wafer from the second location toward the first location. The second position is opposite the first position with respect to a centerline that traverses the top surface of the wafer. A step of forming a meniscus of electroplating solution between the anode and the top surface of the wafer is further performed. By forming the meniscus, it is possible to pass a current between the anode and the first electrode via the meniscus. The method further includes contacting the second electrode against the wafer at the second position when the anode has traversed the upper surface of the wafer a sufficient distance from the second position. The step of bringing the second electrode into contact with the wafer makes it possible to pass a current between the anode and the second electrode via the meniscus. After the step of bringing the second electrode into contact with the wafer, the method includes another step of separating the first electrode from the wafer. The method continues with completing the anode traversal at the top surface of the wafer.

  Other aspects and advantages of the present invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the present invention.

  The invention, together with further advantages thereof, may best be understood by referring to the following detailed description in conjunction with the accompanying drawings.

  In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order not to unnecessarily obscure the present invention.

  FIG. 1A is a diagram illustrating an apparatus for electroplating a semiconductor wafer according to one embodiment of the present invention. The apparatus includes a wafer support 103 configured to hold the wafer 101 firmly. The apparatus further includes a first electrode 107A and a second electrode 107B. Each of the first electrode 107 </ b> A and the second electrode 107 </ b> B is disposed close to the outer periphery of the wafer support portion 103. In addition, the second electrode 107 </ b> B is disposed at a position substantially opposite to the first electrode 107 </ b> A with respect to the wafer support portion 103. In one embodiment, the first electrode 107 </ b> A is disposed at a first position close to the outer periphery of the wafer support 103. The first position exists along the first semi-perimeter of the wafer support. Further, in the same embodiment, the second electrode is disposed at a second position close to the outer periphery of the wafer support portion 103. The second position exists along the second semi-periphery of the wafer support 103 except for the first semi-periphery of the wafer support 103.

  Each of the first electrode 107A and the second electrode 107B is configured to move for electrical connection and disconnection from the wafer 101, as indicated by arrows 113A and 113B, respectively. It should be understood that the movement of the electrodes 107A and 107B for connection and disconnection from the wafer 101 can be performed in an infinite number of ways. For example, in one embodiment, the electrodes 107A and 107B can be moved linearly in a plane along the wafer. In another embodiment, the electrodes 107A and 107B have a sufficiently elongated shape and are arranged so that the elongated shape is coplanar with the wafer 101. The electrodes 107A and 107B can be brought into contact with the wafer by rotating. Further, it should be understood that the shape of electrodes 107A and 107B can be defined in a number of different shapes. For example, in one embodiment, the electrodes 107A and 107B can be substantially rectangular in shape. In another embodiment, the electrodes 107A and 107B may have a rectangular shape having a curvature whose side in contact with the wafer matches the curvature of the outer periphery of the wafer. In yet another embodiment, the electrodes 107A and 107B can be C-shaped. It should be understood that the present invention requires at least two electrodes that can be operated independently for electrical connection and disconnection from the wafer.

The apparatus of FIG. 1A further includes an anode 109 configured to be disposed above the upper surface of the wafer 101. In one embodiment, the horizontal surface of the anode facing the wafer 101 is defined to have a generally rectangular surface area that is substantially parallel to the wafer 101. The rectangular surface area is defined to have a first dimension that is greater than or equal to the diameter of the wafer. In the view shown in FIG. 1A, the first dimension of the rectangular surface region extends toward the back of the page. The rectangular surface area further includes a second dimension defined to be less than the diameter of the wafer. In one embodiment, the second dimension is significantly smaller than the wafer diameter. With respect to the view shown in FIG. 1A, the second dimension of the rectangular surface region extends perpendicular to the direction in which the first dimension extends and parallel to the wafer support 103. When the anode 109 is placed over the wafer 101, the first dimension of the rectangular area, ie, the long dimension, extends along the first chord across the wafer 101. Accordingly, the anode 109 will extend completely across the wafer in the direction of the first string. Further, the second dimension of the rectangular region, ie, the short dimension, extends in the direction of the second chord across the wafer 101. The second string is perpendicular to the first string. Regardless of the position of the anode 109 above the wafer 101, it should be understood that the anode 109 does not extend completely across the wafer in the direction of the second string.

  The anode 109 is configured to move on the wafer 101 in a direction connecting the second electrode 107B and the first electrode 107A, as indicated by an arrow 115. That is, the anode 109 is configured to move in the direction of the second string. When the anode 109 is moved on the wafer 101, the anode 109 has a direction along the first dimension of the rectangular surface region facing the wafer, that is, a direction along the long dimension is approximately the moving direction. Oriented to be vertical. Therefore, the anode 109 can traverse the entire upper surface of the wafer 101. Further, when the anode 109 is moved on the wafer 101, the rectangular surface area of the anode 109 is maintained at a distance close to the upper surface of the wafer 101.

  The distance between the rectangular surface area of the anode 109 and the wafer 101 is such that the meniscus 111 of the electroplating solution is maintained between the anode 109 and the top surface of the wafer 101 as the anode 109 traverses over the wafer 101. It will be enough. In addition, the meniscus 111 can be confined within the volume directly below the anode 109. Meniscus confinement can be achieved in a variety of ways, as described below. In one embodiment, the anode 109 is formed of a solid consumable anode material. In this embodiment, the electroplating solution meniscus 111 is formed in a volume directly below the anode 109 by flowing the electroplating solution around the anode. This embodiment is further described below with reference to FIGS. 4A and 4B. In another embodiment, anode 109 is defined as a virtual anode formed from a porous resistive material. In this embodiment, the meniscus 111 of the electroplating solution can be supplied to the volume directly below the virtual anode by flowing the electroplating solution containing cations through the porous virtual anode. This embodiment is further described below with reference to FIGS. 5A and 5B.

  It should be understood that during operation of the apparatus of FIG. 1A, the anode 109 and at least one of the first and second electrodes 107A / 107B are electrically connected to a power source such that a potential difference exists therebetween. That is, when a meniscus 111 of electroplating solution exists between the anode 109 and the wafer 101 and either the first electrode 107A or the second electrode 107B is electrically connected to the wafer 101, the current is: It flows between the anode 109 and the connected electrode. An electroplating reaction can occur in a portion exposed to the meniscus 111 of the electroplating solution on the upper surface of the wafer 101 due to a current flowing between the anode 109 and the connected electrode, that is, 107A and / or 107B. .

  The apparatus of FIG. 1A is further configured to protect the first electrode 107A and the second electrode 107B from exposure of the electroplating solution to the meniscus 111 as the anode 109 and meniscus 111 pass over, respectively. Fluid shields 105A and 105B. In one embodiment, each of the first and second electrodes 107A / 107B is moved away from the wafer 101 as the anode 109 and the meniscus 111 of the electroplating solution pass over the respective fluid shield. It can be controlled to be stored under 105A / 105B.

  FIG. 1B illustrates an apparatus for electroplating a semiconductor wafer according to another embodiment of the present invention. The apparatus of FIG. 1B is configured to move the wafer support portion 103, the electrodes 107A / 107B, and the fluid shields 105A / 105B together in the linear direction indicated by the arrow 117 under the anode 109 maintained at a fixed position. Except that it is equivalent to that of FIG. 1A. It should be understood that during operation of the device of FIG. 1B, the anode 109 is oriented in the same manner as the anode in the device of FIG. 1A described above. Further, the electrodes 107A / 107B are controlled for electrical connection and disconnection from the wafer 101 based on the position of the anode 109, similarly to the electrode of the apparatus of FIG. 1A described above. It should be understood that the apparatus of FIG. 1B can easily prevent the deposition of unwanted foreign particles on the top surface of the wafer 101 because the apparatus of FIG. 1B does not need to move equipment above the wafer 101.

  2A to 2D are a series of diagrams illustrating the operation of the apparatus for electroplating the semiconductor wafer shown in FIG. 1A described above, according to one embodiment of the present invention. FIG. 2A shows the device immediately after the start of the electroplating process. In FIG. 2A, the anode 109 traverses the upper surface of the wafer 101. The meniscus 111 is formed under the anode 109. As shown in FIG. 2A, the fluid shield 105B serves to protect the second electrode 107B from the meniscus 111 of the electroplating solution as the anode passes over it. Further, the second electrode 107B is electrically disconnected from the wafer 101, and is held in the retracted position when the anode 109 and the meniscus 111 pass above. Further, the first electrode 107 positioned substantially opposite to the anode 109 on the upper surface of the wafer is positioned so as to be electrically connected to the wafer 101. Therefore, current flows from the anode 109 through the meniscus and across the upper surface of the wafer 101 to the electrode 107A. In FIG. 2A, the meniscus 111 is generally confined within the volume directly below the anode 109. Furthermore, since the first electrode 107A is located at a sufficient distance from the anode 109, the first electrode 107A is not exposed to the electroplating solution.

  FIG. 2B shows the apparatus as the anode 109 continues across the wafer 101 from the position shown in FIG. 2A. The first electrode 107A maintains a state of being connected to the wafer 101 when the anode 109 moves away from the second electrode 107B and crosses toward the first electrode 107A. In one embodiment, the second electrode 107B is in the retracted position until the anode 109 and the meniscus 111 are separated from the second electrode 107B by a sufficient distance to ensure that the second electrode is not exposed to the electroplating solution. Maintained.

  Further, the connection of the first electrode 107A and the second electrode 107B to the wafer 101 is managed in order to optimize the current distribution existing in the portion in contact with the meniscus 111 on the upper surface of the wafer 101. In one embodiment, it is desirable to maintain an approximately uniform current distribution at the interface between the meniscus 111 and the wafer 101 as the anode 109 traverses over the wafer 101. It should be understood that by maintaining the anode 109 at a sufficient distance from the connected electrode, ie, the cathode, the current distribution at the interface between the meniscus 111 and the wafer 101 can be made more uniform. Thus, in one embodiment, the transition from the connection of the first electrode 107A to the connection of the second electrode 107B occurs when the anode 109 is substantially close to the centerline of the upper surface of the wafer 101. Here, the center line is perpendicular to the transverse direction of the anode 109.

  During the transition from the connection of the first electrode 107A to the connection of the second electrode 107B, the connection of the first electrode 107A to the wafer 101 is maintained until the second electrode 107B is connected. After the second electrode 107B is connected, the first electrode is disconnected from the wafer 101. Maintaining at least one electrode connected to the wafer 101 serves to minimize the possibility of gaps or biases in the deposition of material produced by the electroplating process.

  FIG. 2C shows the device after the transition from the connection of the first electrode 107A to the connection of the second electrode 107B as the anode 109 continues across the wafer 101 toward the first electrode 107A. The second electrode 107 </ b> B is illustrated as being connected to the wafer 101. The first electrode 107A is illustrated as being stored under the fluid shield 105A to be disconnected from the wafer 101 and protected from the meniscus 111 of the approaching electroplating solution. The current flows from the anode 109, through the meniscus 111, across the upper surface of the wafer 101, and to the second electrode 107B.

  FIG. 2D shows the apparatus when the anode 109 approaches the first electrode 107A and is nearing completion of traversal on the wafer 101. FIG. The fluid shield 105A serves to protect the first electrode 107A from the meniscus 111 of the electroplating solution as the anode 109 passes over it. Further, the first electrode 107A is electrically disconnected from the wafer 101, and is held in the retracted position when the anode 109 and the meniscus 111 pass above.

  3A is a diagram showing a top view of the anode 109 relative to the first electrode 107A, the second electrode 107B, and the wafer 101 previously shown in FIG. 2B. As described above, the anode 109 extends completely across the wafer 101 in the direction of the long dimension. Thus, when the anode 109 is traversed over the wafer 101, the entire upper surface of the wafer 101 is exposed to the meniscus of the electroplating solution present under the anode 109. Further, in the embodiment of FIG. 3A, the first and second electrodes 107A / 107B are illustrated as rectangular bars. However, as described above, the first and second electrodes 107A / 107B can be defined to have any suitable shape compatible with the electroplating process. Furthermore, three or more electrodes can be used in the device to achieve the functions described above.

  FIG. 3B shows an apparatus according to one embodiment of the present invention. The apparatus of FIG. 3B is a diagram showing an apparatus in which a pair of electrodes is used in place of each of the first electrode 107A and the second electrode 107B in the apparatus of FIG. 3A. Further, each of the electrodes shown in FIG. 3B is illustrated as having an alternative shape. As described above, the present invention can be implemented by a large number of electrodes having various shapes as long as the large number of electrodes are arranged along the center line of the wafer 101 so as to face each other. Furthermore, in the present invention, the electrodes on the respective sides facing each other along the center line of the wafer 101 need to be independently controllable with respect to contact with the wafer 101.

  FIG. 4A is a diagram illustrating a solid anode 109A that traverses the wafer 101 in one direction 115 in one embodiment of the invention. As described above, the anode 109 can be a solid anode 109A formed of a consumable anode material. In this embodiment, the meniscus 111 of electroplating solution is supplied to the area directly below the solid anode 109A by flowing the electroplating solution around the solid anode 109A. More specifically, the electroplating solution 401 is supplied to a position on the upper surface of the solid anode 109A via a tube. Then, the electroplating solution 401 flows through the trough 405 to the front edge of the solid anode 109A. At the leading edge of solid anode 109A, electroplating solution 401 flows over the leading edge as indicated by callout 403 and flows below solid anode 109A to form meniscus 111.

  FIG. 4B is a diagram showing a top view of the solid anode 109A shown in FIG. 4A described above. The trough 405 is oriented to direct the flow of the electroplating solution to the front of the solid anode 109A. The front portion of the solid anode 109 </ b> A is an edge on the traveling direction side of the solid anode 109 </ b> A in the transverse direction 115 on the wafer 101. The top view of the solid anode 109A further shows a suction hole 407 located at the end of the solid anode 109A. The suction hole 407 serves to draw the electroplating solution 401 of the meniscus 111 toward the end of the solid anode 109A. The suction hole 407 allows the electroplating solution 401 to flow in the meniscus 111 region while confining the electroplating solution 401 in the meniscus 111 region. However, it is understood that the present invention contemplates other methods of supplying and managing the electroplating solution 401 in the meniscus 111 region in addition to those explicitly described herein when using the solid anode 109A. I want. The principles of the present invention remain the same regardless of the particular method used to supply and manage the electroplating solution 401 within the meniscus 111 region.

FIG. 5A is a diagram showing the above-described virtual anode 109B traversing the wafer 101 in one direction 115 in one embodiment of the present invention. The virtual anode 109B includes a porous resistance material 501. The electroplating solution 505 containing cations can pass through the porous resistive material 501 and form a meniscus in the region directly below the virtual anode 109B. One or more walls 503 can be used to confine the electroplating solution 505 containing cations in a volume that contacts the upper side of the porous resistive material 501. In one embodiment, the porous resistive material 501 can be formed of a ceramic such as Al ₂ O ₃ . However, it should be understood that other porous resistive materials can be used for the virtual anode.

  FIG. 5B is a diagram showing the meniscus confinement surface 507 incorporated in the virtual anode 109B shown in FIG. 5A in one embodiment of the present invention. In the virtual anode 109B, the meniscus confinement surface 507 represents one or more surfaces extending downward of the porous resistive material toward the wafer 101. The meniscus confinement surface 507 is configured to assist in confining the meniscus in the region below the virtual anode 109B. Meniscus confinement surface 507 is illustrated with respect to virtual anode 109B for illustrative purposes. It should be understood that the meniscus confinement surface 507 is equally applicable to the solid anode described above. In one embodiment, the meniscus confinement surface 507 can actually be formed as an integral part of the solid anode.

  A key feature of the electroplating apparatus and method of the present invention is that it can be kept dry when the electrodes and corresponding wafer contact surfaces are in physical contact. The wafer surface conditioning device can be arranged to follow the anode as it crosses the wafer. Thereby, the electrode and the corresponding wafer contact surface can be ensured in a properly dried state.

  FIG. 6 is a diagram illustrating the configuration of a wafer surface conditioning device configured to follow an anode as it traverses over the wafer surface in one embodiment of the present invention. For illustrative purposes, FIG. 6 illustrates the configuration of the wafer surface conditioning device along with the configuration of the virtual anode. However, it should be understood that the wafer surface conditioning device configuration can be used in conjunction with the solid anode described above. Each wafer surface conditioning device can be described as a vent configured to supply fluid at the surface of the wafer or to remove fluid. Each vent is configured to have a length corresponding to the length of the anode and a width sufficient to provide an appropriate fluid flow range.

  In FIG. 6, a first vent 601 is a suction hole and removes fluid from the wafer surface after the anode has passed over it. The second vent 605 is separated from the first vent 601 by a wall 603. The second vent 605 supplies a cleaning fluid to the surface of the wafer. In one embodiment, the cleaning fluid is deionized water. However, in other embodiments, any cleaning fluid suitable for use in wafer processing applications can be used. Third vent 609 is separated from second vent 605 by wall 607. Similar to the first vent 601, the third vent 609 is a suction hole and removes fluid from the surface of the wafer. The fourth vent 613 is separated from the third vent 609 by the wall 611. Further, the fourth vent 613 is defined by the outer wall 615. A fourth vent 613 can be used to supply an isopropyl alcohol (IPA) / nitrogen mixture to the surface of the wafer. It should be understood that the present invention can be implemented using a wafer surface conditioning device that includes a portion of the vent described with reference to FIG. Further, the present invention can be practiced using other wafer surface conditioning devices not explicitly described herein.

  During the plating process, the uniformity of the deposited material depends on the current distribution at the area of the wafer being plated, i.e., the interface between the electroplating solution meniscus and the wafer. Numerous factors can affect the current distribution in the area of the wafer being plated. The three main factors that influence the current distribution are: 1) the position and number of electrodes in contact with the wafer, 2) the resistivity on the top surface of the wafer, and 3) the position and placement of the anode relative to the plated area. included. By introducing a uniformly distributed resistance path, such as a porous resistive material, between the area directly in contact with the cathode, i.e., the plated area, and the true anode and cathode, the current flux is , Uniformly distributed between the uniformly distributed resistance path and the cathode. In addition, by selecting a porous resistive material with a sufficiently large resistance, the effect of the resistivity on the top surface of the wafer can be separated and minimized, especially at the edge of the wafer, thereby making the subsequent plating process uniform. Improved.

  A conventional electroplating system configured to plate the entire wafer at the same time, on the very high resistance barrier film on the wafer surface, unless it has a low resistance intermediate film previously applied to the wafer. Can't be plated. For example, in the case of Cu plating on a very resistive barrier film, conventional systems require a PVD Cu seed layer to be applied prior to the full wafer plating process. Without this seed layer, a drop in resistance across the wafer induces a bipolar effect during full wafer plating. The bipolar effect causes plating separation and etching in the area adjacent to the electrode that contacts the wafer. Furthermore, in the conventional full wafer plating system, it is necessary to uniformly distribute the electrodes on the outer periphery of the wafer and to equalize the resistances of the uniformly distributed electrodes. In conventional full-wafer electroplating systems, the presence of asymmetric contact resistance between one electrode and another causes a non-uniform current distribution across the wafer, which results in non-uniform material deposition across the wafer. appear.

  The electroplating apparatus of the present invention described herein solves the above problems associated with conventional full wafer electroplating systems. More specifically, the apparatus of the present invention can maintain the electrodes in a dry state upon contact with the wafer. When the bar-shaped anode of the present invention traverses the wafer, the electrode (s) can be brought into contact with the portion of the wafer surface that is away from the anode and has increased resistance. Thus, the current present in the cathode, i.e. the area plated under the anode, is evenly distributed. Furthermore, the dry electrode contact approach essentially eliminates the possibility of bipolar effects.

  FIG. 7 is a flowchart illustrating a method for electroplating a semiconductor wafer in one embodiment of the present invention. The method includes a step 701 of contacting a first electrode to a wafer at a first location. In step 703, the second electrode is separated from the wafer at a second location. The second position is on the opposite side of the first position in the center line across the top surface of the wafer. The method further includes a step 705 of traversing the anode from the second position toward the first position on the upper surface of the wafer. In one embodiment, the traversing step is accomplished by holding the anode in a fixed position while moving the wafer. In another embodiment, the traversing step is accomplished by holding the wafer in a fixed position while moving the anode. In step 707, a meniscus of electroplating solution is formed between the anode and the top surface of the wafer so that current flows between the anode and the first electrode through the meniscus. The meniscus is confined between the anode and the top surface of the wafer as the anode crosses the top surface of the wafer.

  The method further includes a step 709 of contacting the second electrode to the wafer at the second position when the anode has traversed the upper surface of the wafer a sufficient distance from the second position. When the second electrode is abutted at the second position, current flows between the anode and the second electrode via the meniscus. In one embodiment, a sufficient distance from the second location is defined to maintain an appropriate current density distribution at the meniscus. The sufficient distance from the second position is further determined to ensure that each of the first and second electrodes is dry with respect to the meniscus of the electroplating solution. The method continues with step 711 of separating the first electrode from the wafer after the step of contacting the second electrode to the wafer. Thereafter, in step 713, the anode traversal is completed at the top surface of the wafer.

  In one embodiment, the step of separating each of the first and second electrodes from the wafer includes positioning each of the corresponding electrodes under the fluid shield. The fluid shield serves to protect each of the first and second electrodes from the meniscus of the electroplating solution. Further, in another embodiment, the method may include cleaning a portion of the upper surface of the wafer immediately after the anode has traversed. Then, you may perform the process of drying the part which cleaned on the upper surface of a wafer.

  While the present invention has been described in terms of several embodiments, those skilled in the art can read the above specification and review the drawings to illustrate various modifications, additions, substitutions, and equivalents. It will be understood that things can be realized. Accordingly, the present invention includes all such modifications, additions, substitutions, and equivalents that fall within the true spirit and scope of the present invention.

The figure which shows the apparatus which electroplates a semiconductor wafer in one embodiment of this invention. The figure which shows the apparatus which electroplates a semiconductor wafer in another embodiment of this invention. The figure which shows operation | movement of the apparatus which electroplates the semiconductor wafer of FIG. 1A mentioned above in one embodiment of this invention. The figure which shows operation | movement of the apparatus which electroplates the semiconductor wafer of FIG. 1A mentioned above in one embodiment of this invention. The figure which shows operation | movement of the apparatus which electroplates the semiconductor wafer of FIG. 1A mentioned above in one embodiment of this invention. The figure which shows operation | movement of the apparatus which electroplates the semiconductor wafer of FIG. 1A mentioned above in one embodiment of this invention. The top view of the anode shown in FIG. 2B is a figure which shows relatively with a 1st electrode, a 2nd electrode, and a wafer. The figure which shows the apparatus by which the electrode pair was used instead of each of the 1st electrode and the 2nd electrode in the apparatus of FIG. 3A in one embodiment of this invention. In one embodiment of the present invention, a diagram illustrating a solid anode traversing in one direction on a wafer The figure which shows the top view of the solid anode shown to FIG. 4A mentioned above. The figure which shows the virtual anode 109B mentioned above which crosses on a wafer in one direction in one embodiment of this invention. The figure which shows what incorporated the meniscus confinement surface in the virtual anode shown to FIG. 5A in one embodiment of this invention. FIG. 3 illustrates a configuration of a wafer surface conditioning device configured to follow an anode as the anode traverses over the wafer surface in one embodiment of the present invention. The figure which shows the flowchart of the method of electroplating a semiconductor wafer in one embodiment of this invention.

Claims (32)

An apparatus for electroplating a semiconductor wafer,
A wafer support configured to hold the wafer;
A first electrode disposed at a first position proximate to an outer periphery of the wafer support and movable to perform electrical connection and disconnection with the wafer held by the wafer support;
Electricity between the wafer supporting portion and the wafer held by the wafer supporting portion is disposed at a second position which is close to the outer periphery of the wafer supporting portion and is substantially opposite to the first position with respect to the wafer supporting portion. A second electrode movable to effect connection and disconnection;
An anode configured to be disposed above the upper surface of the wafer held by the wafer support and having a rectangular surface area, the rectangular surface area being substantially parallel to the upper surface of the wafer An anode defined by a first dimension greater than or equal to the diameter of the wafer and a second dimension smaller than the diameter of the wafer;
With
The first electrode and the second electrode are arranged so that the anode can traverse the entire upper surface of the wafer when the wafer is held by the wafer support. An apparatus for electroplating semiconductor wafers that is configured to move relatively in the direction of linking. In the apparatus which electroplates the semiconductor wafer of Claim 1,
The proximity of the rectangular surface area of the anode to the upper surface of the wafer is such that the rectangular surface area of the anode contacts a meniscus of an electroplating solution supplied to the upper surface area of the wafer. Equipment for electroplating semiconductor wafers that are close enough. In the apparatus which electroplates the semiconductor wafer of Claim 2,
Either the first electrode or the second electrode moved by the contact between the rectangular surface region of the anode and the meniscus so that an electric current passes through the meniscus and is electrically connected to the wafer. Equipment for electroplating semiconductor wafers flowing into The apparatus for electroplating a semiconductor wafer according to claim 2 further comprises:
When the anode traverses over the first electrode, the first electrode is moved to electrically disconnect it from the wafer and the first from exposure of the electroplating solution to the meniscus. A first fluid shield configured to protect one electrode;
When the anode traverses over the second electrode, the second electrode is moved to electrically disconnect it from the wafer and the first from exposure of the electroplating solution to the meniscus. A second fluid shield configured to protect the second electrode;
An apparatus for electroplating a semiconductor wafer comprising: In the apparatus which electroplates the semiconductor wafer of Claim 2,
The rectangular surface region of the anode is a porous structure configured to allow passage of an electroplating solution containing cations to form a meniscus of the electroplating solution on the surface of the wafer. Equipment for electroplating semiconductor wafers made of resistive materials. In the apparatus which electroplates the semiconductor wafer of Claim 1,
The rectangular surface region of the anode is formed of a consumable anode material. An apparatus for electroplating a semiconductor wafer. In the apparatus which electroplates the semiconductor wafer of Claim 1,
The anode is configured to remain in a fixed position, and the wafer support is configured to move relative to the anode. An apparatus for electroplating a semiconductor wafer. In the apparatus which electroplates the semiconductor wafer of Claim 1,
The wafer support is configured to remain in a fixed position, and the anode is configured to move relative to the wafer support. An apparatus for electroplating a semiconductor wafer. An apparatus for electroplating a semiconductor wafer,
A wafer support configured to hold the wafer;
Proximate to the outer periphery of the wafer support and located at a first position along the first semi-perimeter of the wafer support and movable to make electrical contact with the wafer held by the wafer support A first electrode configured in
Proximate to the outer periphery of the wafer support and disposed at a second position along the second semi-periphery of the wafer support excluding the first semi-periphery of the wafer support, and by the wafer support A second electrode configured to be movable to be in electrical contact with the wafer to be held;
An anode configured to be disposed above the upper surface of the wafer held by the wafer support and having a rectangular surface area, the rectangular surface area being substantially parallel to the upper surface of the wafer An anode defined by a first dimension greater than or equal to the diameter of the wafer and a second dimension smaller than the diameter of the wafer;
With
The first electrode and the second electrode are arranged so that the anode can traverse the entire upper surface of the wafer when the wafer is held by the wafer support. An apparatus for electroplating semiconductor wafers that is configured to move relatively in the direction of linking. In the apparatus which electroplates the semiconductor wafer of Claim 9,
The proximity of the rectangular surface area of the anode to the upper surface of the wafer is such that the rectangular surface area of the anode contacts a meniscus of an electroplating solution supplied to the upper surface area of the wafer. Equipment for electroplating semiconductor wafers that are close enough. In the apparatus which electroplates the semiconductor wafer of Claim 10,
Either the first electrode or the second electrode moved by the contact between the rectangular surface region of the anode and the meniscus so that an electric current passes through the meniscus and is in electrical contact with the wafer. Equipment for electroplating semiconductor wafers flowing into The apparatus for electroplating a semiconductor wafer according to claim 10 further comprises:
When moving the first electrode away from the wafer as the anode crosses over the first electrode, the first electrode is removed from exposure of the electroplating solution to the meniscus. A first fluid shield configured to protect;
When moving the second electrode away from the wafer as the anode crosses over the second electrode, the second electrode is removed from exposure of the electroplating solution to the meniscus. A second fluid shield configured to protect;
An apparatus for electroplating a semiconductor wafer comprising: In the apparatus which electroplates the semiconductor wafer of Claim 10,
The rectangular surface region of the anode is a porous structure configured to allow passage of an electroplating solution containing cations to form a meniscus of the electroplating solution on the surface of the wafer. Equipment for electroplating semiconductor wafers made of resistive materials. In the apparatus which electroplates the semiconductor wafer of Claim 9,
The rectangular surface region of the anode is formed of a consumable anode material. An apparatus for electroplating a semiconductor wafer. In the apparatus which electroplates the semiconductor wafer of Claim 9,
The anode is configured to remain in a fixed position, and the wafer support is configured to move relative to the anode. An apparatus for electroplating a semiconductor wafer. In the apparatus which electroplates the semiconductor wafer of Claim 9,
The wafer support is configured to remain in a fixed position, and the anode is configured to move relative to the wafer support. An apparatus for electroplating a semiconductor wafer. A semiconductor wafer electroplating system,
A wafer support structure defined to hold the wafer;
An anode configured to traverse over the wafer support structure from a first position to a second position, each located near and outside an outer periphery of the wafer support structure,
The anode is further configured to contact a meniscus of an electroplating solution between a horizontal surface of the anode and an upper surface of the wafer held by the wafer support structure;
The horizontal surface of the anode has a rectangular region extending along a first chord across the wafer held by the wafer support structure;
The rectangular region is defined by a first dimension that is greater than or equal to the diameter of the wafer, and is further defined by a second dimension that is less than the diameter of the wafer;
The first string is substantially perpendicular to a second string extending from the first position to the second position;
A first electrode configured to be movable to be in electrical contact with the wafer held by the wafer support structure at a first contact position substantially proximate to the first position;
A second electrode configured to be movable to be in electrical contact with the wafer held by the wafer support structure at a second contact position substantially proximate to the second position;
A semiconductor wafer electroplating system. The semiconductor wafer electroplating system according to claim 17,
The meniscus of the electroplating solution is confined in a region between the horizontal surface of the anode having the rectangular region and the top surface of the wafer. The semiconductor wafer electroplating system according to claim 17,
Contact between the anode and the meniscus of the electroplating solution causes the first electrode or the second electrode to be moved in electrical contact with the wafer through the meniscus of the electroplating solution. A semiconductor wafer electroplating system that flows to one of the electrodes. The semiconductor wafer electroplating system according to claim 17,
When moving the first electrode away from the wafer as the anode crosses over the first electrode, the first electrode is removed from exposure of the electroplating solution to the meniscus. A first fluid shield configured to protect;
When moving the second electrode away from the wafer as the anode crosses over the second electrode, the second electrode is removed from exposure of the electroplating solution to the meniscus. A second fluid shield configured to protect;
A semiconductor wafer electroplating system comprising: The semiconductor wafer electroplating system according to claim 17,
The horizontal surface of the anode having the rectangular region is formed by a porous resistive material configured to allow passage of an electroplating solution containing cations to form a meniscus of the electroplating solution. Semiconductor wafer electroplating system. The semiconductor wafer electroplating system according to claim 17,
The horizontal surface of the anode having the rectangular region is formed of a consumable anode material. The semiconductor wafer electroplating system according to claim 17,
The anode is configured to remain in a fixed position, and the wafer support is configured to move relative to the anode. Semiconductor wafer electroplating system. The semiconductor wafer electroplating system according to claim 17,
The wafer support is configured to remain in a fixed position, and the anode is configured to move relative to the wafer support. Semiconductor wafer electroplating system. A method for electroplating a semiconductor wafer comprising:
Bringing the first electrode into contact with the wafer at the first position;
Traversing the anode at the upper surface of the wafer from a second position opposite the first position to a first line relative to a centerline traversing the upper surface of the wafer;
Here, the anode has a rectangular area determined so as to be substantially parallel to the upper surface of the wafer, and the rectangular area has a first dimension equal to or larger than the diameter of the wafer, The region is further defined by a second dimension that is smaller than the diameter of the wafer;
By forming a meniscus of an electroplating solution between the anode and the upper surface of the wafer, a current is passed between the anode and the first electrode via the meniscus,
When the anode has traversed the upper surface of the wafer from the second position by a sufficient distance, the second electrode is brought into contact with the wafer at the second position, via the meniscus, A current is passed between the anode and the second electrode;
After contacting the second electrode, the first electrode is separated from the wafer,
A method of electroplating a semiconductor wafer that completes traversing the anode on the top surface of the wafer. The method for electroplating a semiconductor wafer according to claim 25 further comprises:
A method of electroplating a semiconductor wafer that separates the second electrode from the wafer before the anode crosses the second position. The method of electroplating a semiconductor wafer according to claim 26 ,
Detaching each of the first and second electrodes from the wafer includes positioning each of the electrodes under a fluid shield;
The method of electroplating a semiconductor wafer, wherein the fluid shield serves to protect each of the electrodes from the meniscus of the electroplating solution. The method of electroplating a semiconductor wafer according to claim 25 ,
The sufficient distance from the second position maintains an appropriate current density distribution in the meniscus and ensures that each of the first and second electrodes is dry with respect to the meniscus of the electroplating solution. A method of electroplating a semiconductor wafer that is defined to be. The method of electroplating a semiconductor wafer according to claim 25 ,
The method of electroplating a semiconductor wafer, wherein the traversing is performed by holding the anode in a fixed position while moving the wafer. The method of electroplating a semiconductor wafer according to claim 25 ,
The method of electroplating a semiconductor wafer, wherein the traversing is performed by holding the wafer in a fixed position while moving the anode. The method for electroplating a semiconductor wafer according to claim 25 further comprises:
A method of electroplating a semiconductor wafer that confines the meniscus between the anode and the top surface of the wafer as the anode crosses the top surface of the wafer. The method for electroplating a semiconductor wafer according to claim 25 further comprises:
Cleaning the top surface of the wafer immediately after the anode has traversed;
A method of electroplating a semiconductor wafer for drying the cleaned portion on the upper surface of the wafer.

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